In this paper the path planning for obstacle-avoided pursuit problem (OAP) is studied. The OAP models based on the mixed integer linear programming (MILP) is presented. In the OAP models, the dynamic equation of mass point with linear damping is taken as the state equation of vehicle's motion. Integer variables are used to describe the relative position of vehicle and obstacles. "Expansible Target Size" is proposed to describe the pursuit process for target step-by-step. "Pursuit Direction" of vehicle is defined. The Isometric Plane Method selected integer variables is used to solve MILP pursuit problem. How to select the integer variables of inner point is also given. Finally, simulations are given to show the efficiency of the method.